The Northeastern United States blizzard of 1978 was a catastrophic, historic nor'easter that struck New England, New Jersey, Pennsylvania and the New York metropolitan area. The Blizzard of '78 formed on Sunday, February 5, 1978, and broke up on February 7. The storm was primarily known as "Storm Larry" in Connecticut, following the local convention promoted by the Travelers Weather Service on television and radio stations there. Snow fell mostly from Monday morning, February 6, to the evening of Tuesday, February 7. Connecticut, Rhode Island, and Massachusetts were hit especially hard by this storm.

Boston received a record-breaking 27.1 inches (69 cm) of snow; Providence also broke a record, with 27.6 inches (70 cm) of snow; Atlantic City broke an all-time storm accumulation, with 20.1 inches (51 cm), two Philadelphia suburban towns in Chester County received 20.2 inches (51 cm) while the City of Philadelphia received 16.0 inches (41 cm). Nearly all economic activity was disrupted in the worst-hit areas. The storm killed about 100 people in the Northeast and injured about 4,500. It caused more than US$520 million (US$2.06 billion in 2020 terms) in damage.